1. Field of the Invention
The present disclosure relates to overvoltage protection, and more particularly to overvoltage protection for communications buses.
2. Description of Related Art
Vehicles, like aircraft, commonly carry electrical devices. The electrical devices provide various functionality responsive to command inputs received through a communications bus, which extends through the vehicle and interconnects the electrical devices with user interfaces or controllers. The communications bus generally conveys the command input to electronics associated with the electrical device, typically through a low voltage command signal applied to the electronics through a signaling lead. The low voltage electronics can require overvoltage protection, such as can occur from a lightning strike or short between the vehicle power bus and the communications bus, typically with a fuse or positive temperature coefficient (PTC) device.
Fuses are generally single-use and require replacement after tripping. Where the fuse is contained within a line-replaceable-unit (LRU), restoration of functionality requires replacement of the LRU subsequent to the fuse tripping. PTC devices generate reset automatically after tripping, the overcurrent triggering a PTC heating/cooling cycle that disconnects and reconnects the electronics to the communications bus in response to the overvoltage. Because PTC devices reset automatically, PTC devices commonly provide overvoltage protection in circuits that are difficult to access or are in remote locations and where the associated heating can be tolerated.
Such conventional systems and methods have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved overcurrent protection devices. The present disclosure provides a solution for this need.